<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>异步地图展示</title>
  <style>
    body, html, #allmap {
      width: 100%;
      height: 100%;
      overflow: hidden;
      margin: 0;
      font-family: "微软雅黑";
    }
  </style>
  <script type="text/javascript" src="https://api.map.baidu.com/api?type=webgl&v=1.0&ak=G1LFyjrNGIkns5OfpZnrCGAKxpycPLwb"></script>
</head>
<body>
  <div id="allmap"></div>
</body>
</html>
<script type="text/javascript">
  function init () {
    let map = new BMapGL.Map("allmap");
    let point = new BMapGL.Point(116.404, 39.915);
    map.centerAndZoom(point, 12);
    map.enableScrollWheelZoom(true);
  }

  function loadScript () {
    let script = document.createElement("script");
    script.src = "https://api.map.baidu.com/api?v=1.0&type=webgl&ak=G1LFyjrNGIkns5OfpZnrCGAKxpycPLwb&callback=init";
    document.body.appendChild(script);
  }

  window.onload = loadScript;
</script>